An epoxy resin composition has excellent electrical performance and adhesion. Therefore, it is widely used in electrical and electronic fields.
In addition, if sufficient effects can not be obtained when a conventional epoxy resin is used alone or in combination, cyanate-epoxy composite resin compositions comprised of mixing epoxy resin with cyanate ester resin are commonly used as a high heat resistant resin composition, for sealing of semiconductor and for molding.
For example, liquid epoxy resin compositions used for sealing of semiconductor comprised of cyanate ester, epoxy resin, inorganic filler and dihydrazide compound etc. have already been proposed (Patent document 1). However, in this case there were disadvantages in that not only each curing agent for cyanate ester and epoxy resin is required respectively, but also a high temperature and long curing time are required for curing. Therefore, liquid epoxy resin composition having satisfactory performance has not been obtained yet.
It was also proposed (Patent document 2) to use an amine curing agent for a composite composition containing cyanate ester and epoxy resin. However, in this case, sufficient storage stability was not obtained.
Furthermore, the heat curable resin composition (Patent document 3), wherein a latent curing agent containing imidazole component was used for cyanate ester and epoxy resin, was proposed. However, in this case, the quantity of cyanate resin used should be limited from a viewpoint of obtaining sufficient storage stability. Therefore, liquid epoxy resin compositions having satisfactory performance have not been obtained yet.
Patent document 1: Japanese Unexamined Patent Publication Tokkai 2001-302767
Patent document 2: Japanese Unexamined Patent Publication Tokkai-sho 60-250026
Patent document 3: Japanese Unexamined Patent Publication Toku hyo 2001-506313